This cancer control project will begin research on the practice of "underdosing" in cancer patient treatment. A sequential series of data collection activities are proposed to explore how the beliefs, perceptions and practices of physicians influence patterns of post- operative care for patients with breast cancer. Specific attention will be drawn to decisions to withhold or reduce adjuvant therapy in patient care. The initial phase of study will determine which physicians in Connecticut are experienced in caring for women with the disease and where such care is rendered. From a roster of cancer therapists throughout the state, 50 practitioners will be randomly selected for interview on topics of the appropriate role of adjuvant therapy in breast cancer management, and the difficulties of administering cancer drugs in routine medical practice. From the responses received, a self-administering survey instrument will be developed and pilot tested for use among a larger cross-section of cancer therapists.